[Tutor] mysqlite

Lolo Lolo losermeloser at yahoo.com
Wed Mar 6 19:50:46 CET 2013


im working through alan's sql tutorial. i have a few questions from there but 1st i wanted to try out an example in Core python's sql example.

>>> import sqlite3
>>> cxn = sqlite3.connect('sqlite_test/test')
>>> cur = cxn.cursor()

after this i created a table called users and inserted some data. then i did:

>>> cur.execute('SELECT * from users')
>>> for user in cur.fetchall():
            print(user)

i got the results of all data i gave the table. then did

>>> cur.close()
>>> cxn.commit()
>>> cxn.close()

i then closed this interactive IDLE session. i reopened another session and simply did 

>>> import sqlite3
>>> cxn = sqlite3.connect('sqlite_test/test')
>>> cur = cxn.cursor()
>>> for user in cur.fetchall():
            print(user)

>>> 
but this time no data was printed back to me, even though the database file 'test' already existed from the previous session. Why did this happen, cant i just connect and my data is still intact? or do i have to always re enter data from the previously saved session?

My questions about http://www.alan-g.me.uk/tutor/tutdbms.htm is to open a database it uses the command line directly and doesnt creat cursor() or connect() objects e.g.
 
E:\PROJECTS\SQL> sqlite3 employee.db 
sqlite> create table Employee
   ...> (EmpID,Name,HireDate,Grade,ManagerID);
sqlite> insert into Employee (EmpID, Name, HireDate, Grade, ManagerID)
   ...> values ('1020304','John Brown','20030623','Foreman','1020311');
 
i tried this in my command line but got :
python.exe: can't open file 'sqlite': [Errno 2] No
 such file or directory
 
i tried creating the a folder called test and doing:  test employee.db 
but no test.db was created.
 
my main questions are it possible to use the command line without cursor() and connect() in python 3 or is it only for python 2. is it better from the command line or in a .py file. And also my previous question i had about having to re enter previously stored data         


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